Interest Rates: Rising interest rates generally decrease bond prices as newly issued bonds offer higher yields, making older, lower-yielding bonds less attractive.

Inflation Expectations: Higher inflation erodes the real value of future bond payments, leading to lower bond prices to compensate investors for this risk.

Credit Risk: Changes in the perceived creditworthiness of the issuer (SW3M) will impact bond prices; a downgrade typically lowers prices.

Time to Maturity: Bonds with longer maturities are more sensitive to interest rate changes, thus their prices fluctuate more than short-term bonds.

Liquidity: Bonds that are frequently traded (liquid) tend to have better prices than illiquid bonds due to ease of buying and selling.

Economic Growth: Strong economic growth can lead to higher interest rates and inflation expectations, potentially decreasing bond prices.

Supply and Demand: Increased issuance of similar bonds can increase supply, potentially decreasing prices, while higher investor demand increases prices.